From ef5cd881119d6a16d5338c9cce09bf654ad46ed7 Mon Sep 17 00:00:00 2001
From: Libby <libby@minds.libby.gamecult.org>
Date: Sun, 8 Nov 2026 15:13:58 +0000
Subject: [PATCH] C#: v0 errors for snapshot, shard log and variant refusals
 carry fixed text, never an exception's message

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
---
 .../CultNetDatabaseServer.cs                  |  7 ++--
 .../CultNetDocumentRegistryVariantTests.cs    |  1 +
 .../CultNetWriteReceiptServerTests.cs         | 32 +++++++++++++++++++
 3 files changed, 37 insertions(+), 3 deletions(-)

diff --git a/src/GameCult.Networking/CultNetDatabaseServer.cs b/src/GameCult.Networking/CultNetDatabaseServer.cs
index 32688434..16967d49 100644
--- a/src/GameCult.Networking/CultNetDatabaseServer.cs
+++ b/src/GameCult.Networking/CultNetDatabaseServer.cs
@@ -266,7 +266,7 @@ namespace GameCult.Networking
             catch (Exception ex)
             {
                 _server.Logger.LogError($"CultNet snapshot v1 request failed: {ex.Message}");
-                peer.SendCultNet(new CultNetErrorMessage { Error = ex.Message });
+                peer.SendCultNet(new CultNetErrorMessage { Error = "the snapshot request could not be answered" });
             }
 
             return Task.CompletedTask;
@@ -286,7 +286,8 @@ namespace GameCult.Networking
             }
             catch (Exception ex)
             {
-                peer.SendCultNet(new CultNetErrorMessage { Error = ex.Message });
+                _server.Logger.LogError($"CultNet shard log request failed: {ex.Message}");
+                peer.SendCultNet(new CultNetErrorMessage { Error = "the shard log request could not be answered" });
             }
 
             return Task.CompletedTask;
@@ -754,7 +755,7 @@ namespace GameCult.Networking
                 var refusedKey = change.GetType().GetProperty("Key")?.GetValue(change) is CultRecordKey changed ? changed.Value : string.Empty;
                 lock (refused)
                     refused.Add(refusedKey);
-                sendError(new CultNetErrorMessage { Error = refusal.Message });
+                sendError(new CultNetErrorMessage { Error = "the record is a variant CultNet cannot carry" });
                 return null;
             }
 
diff --git a/tests/GameCult.Networking.Tests/CultNetDocumentRegistryVariantTests.cs b/tests/GameCult.Networking.Tests/CultNetDocumentRegistryVariantTests.cs
index 64de1093..5713b0da 100644
--- a/tests/GameCult.Networking.Tests/CultNetDocumentRegistryVariantTests.cs
+++ b/tests/GameCult.Networking.Tests/CultNetDocumentRegistryVariantTests.cs
@@ -418,6 +418,7 @@ namespace GameCult.Networking.Tests
                 CultNetDatabaseChangeKind.Added, VariantKey, schemaId, database.Shards[0], cache.Get<VariantWireFixture>(VariantKey)!, previousDocument: null);
             Assert.That(Deliver(databaseServer, added, selection, refused, errors), Is.Null);
             Assert.That(errors, Has.Count.EqualTo(1));
+            Assert.That(errors[0].Error, Is.EqualTo("the record is a variant CultNet cannot carry"));
 
             var removed = new CultNetDatabaseChange<VariantWireFixture>(
                 CultNetDatabaseChangeKind.Removed, VariantKey, schemaId, database.Shards[0], document: null, previousDocument: cache.Get<VariantWireFixture>(VariantKey)!);
diff --git a/tests/GameCult.Networking.Tests/CultNetWriteReceiptServerTests.cs b/tests/GameCult.Networking.Tests/CultNetWriteReceiptServerTests.cs
index eb20b345..09188c5f 100644
--- a/tests/GameCult.Networking.Tests/CultNetWriteReceiptServerTests.cs
+++ b/tests/GameCult.Networking.Tests/CultNetWriteReceiptServerTests.cs
@@ -1087,5 +1087,37 @@ namespace GameCult.Networking.Tests
             Assert.That(session.TryBegin("m1", HashOf("b"), out _), Is.EqualTo(CultNetWriteReceiptSession.Begin.New));
             Assert.That(session.TryBegin("m1", HashOf("b"), out _), Is.EqualTo(CultNetWriteReceiptSession.Begin.Unanswered));
         }
+
+        // ---- Fixed text in v0 errors: an exception's own words never reach the wire ----
+
+        private static Func<TMessage, CultNetServerPeer, Task> HandlerOf<TMessage>(Rig rig, string field) =>
+            (Func<TMessage, CultNetServerPeer, Task>)typeof(CultNetDatabaseServer)
+                .GetField(field, BindingFlags.NonPublic | BindingFlags.Instance)!.GetValue(rig.DatabaseServer)!;
+
+        [Test]
+        public async Task ASnapshotFaultIsAnsweredWithFixedTextNotTheExceptionMessage()
+        {
+            var rig = Build();
+            var wire = new Wire();
+
+            await HandlerOf<CultNetSnapshotRequestV1Message>(rig, "_snapshotHandlerV1")(
+                new CultNetSnapshotRequestV1Message { MessageId = "s1", Selection = null! }, wire.Peer);
+
+            var error = (CultNetErrorMessage)wire.Sent.Single();
+            Assert.That(error.Error, Is.EqualTo("the snapshot request could not be answered"));
+        }
+
+        [Test]
+        public async Task AShardLogFaultIsAnsweredWithFixedTextNotTheExceptionMessage()
+        {
+            var rig = Build();
+            var wire = new Wire();
+
+            await HandlerOf<CultNetShardLogRequestMessage>(rig, "_shardLogHandler")(
+                new CultNetShardLogRequestMessage { MessageId = "l1", ShardId = string.Empty }, wire.Peer);
+
+            var error = (CultNetErrorMessage)wire.Sent.Single();
+            Assert.That(error.Error, Is.EqualTo("the shard log request could not be answered"));
+        }
     }
 }